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The comminuting and soil mixing activities of earthworms can affect soil physical, chemical and biolog-ical properties, which in turn can influence plant growth and survival. Accordingly, there is growing con-cern that the spread of exotic earthworms into northern temperate forests may compromise biodiversityand tree species recruitment. We report on a study where we sampled earthworms, soils, and understoryplants in plots established in 40 mature sugar maple stands distributed over 3 areas in the EasternTownships of Southern Québec (Canada). Earthworms were found in 19 of 40 plots, and earthworm fre-quency of occurrence (Efo) as well as the complexity of earthworm communities reflected human acces-sibility to the plots. Plant species richness decreased, and species evenness increased, withEfo. TheEfowasrelated to a decrease in the cover of 5 plant species, and to an increase in the cover of 2 other plant speciesor plant functional groups. IncreasingEfoalso correlated with higher soil pH, lower forest floor thicknessand lower soil C:N ratio. Among these 3 variables, redundancy analysis (RDA) revealed that soil pH andforest floor thickness correlated with plant community composition. Based on neutral lipid and phospho-lipid fatty acid profiles, we found that soil bacteria and fungi increased with a decrease in forest floorthickness, bacteria and arbuscular mycorrhizal fungi (AMF) increased with soil pH, whereas actinobacte-ria and AMF increased withEfo. We discuss the possible mechanisms by which earthworms might directlyor indirectly alter understory plant community composition. By considering the location and land usemanagement of each study site, our study provides further evidence that the spread of exotic earthwormsin sugar maple stands of Southern Québec may be linked to human activities, with implications for fur-ther research and conservation issues.

Globally, biological invasions can have strong impacts on biodiversity as well as ecosystem functioning. While less conspicuous than introduced aboveground organisms, introduced belowground organisms may have similarly strong effects. Here, we synthesize for the first time the impacts of introduced earthworms on plant diversity and community composition in North American forests. We conducted a meta-analysis using a total of 645 observations to quantify mean effect sizes of associations between introduced earthworm communities and plant diversity, cover of plant functional groups, and cover of native and non-native plants. We found that plant diversity significantly declined with increasing richness of introduced earthworm ecological groups. While plant species richness or evenness did not change with earthworm invasion, our results indicate clear changes in plant community composition: cover of graminoids and non-native plant species significantly increased, and cover of native plant species (of all functional groups) tended to decrease, with increasing earthworm biomass. Overall, these findings support the hypothesis that introduced earthworms facilitate particular plant species adapted to the abiotic conditions of earthworm-invaded forests. Further, our study provides evidence that introduced earthworms are associated with declines in plant diversity in North American forests. Changing plant functional composition in these forests may have long-lasting effects on ecosystem functioning.

The comminuting and soil mixing activities of earthworms can affect soil physical, chemical and biolog-ical properties, which in turn can influence plant growth and survival. Accordingly, there is growing con-cern that the spread of exotic earthworms into northern temperate forests may compromise biodiversityand tree species recruitment. We report on a study where we sampled earthworms, soils, and understoryplants in plots established in 40 mature sugar maple stands distributed over 3 areas in the EasternTownships of Southern Québec (Canada). Earthworms were found in 19 of 40 plots, and earthworm fre-quency of occurrence (Efo) as well as the complexity of earthworm communities reflected human acces-sibility to the plots. Plant species richness decreased, and species evenness increased, withEfo. TheEfowasrelated to a decrease in the cover of 5 plant species, and to an increase in the cover of 2 other plant speciesor plant functional groups. IncreasingEfoalso correlated with higher soil pH, lower forest floor thicknessand lower soil C:N ratio. Among these 3 variables, redundancy analysis (RDA) revealed that soil pH andforest floor thickness correlated with plant community composition. Based on neutral lipid and phospho-lipid fatty acid profiles, we found that soil bacteria and fungi increased with a decrease in forest floorthickness, bacteria and arbuscular mycorrhizal fungi (AMF) increased with soil pH, whereas actinobacte-ria and AMF increased withEfo. We discuss the possible mechanisms by which earthworms might directlyor indirectly alter understory plant community composition. By considering the location and land usemanagement of each study site, our study provides further evidence that the spread of exotic earthwormsin sugar maple stands of Southern Québec may be linked to human activities, with implications for fur-ther research and conservation issues.

We used 37 years of North American Breeding Bird Surveys to test for effects of periodical cicada (Magicicada spp.) emergences on the abundance and spatial synchrony of 24 species of avian predators in hardwood forests of the eastern United States. Fifteen (63%) of the bird species exhibited numerical changes in abundance apparently associated with emergences of the local periodical cicada brood, and intraspecific spatial synchrony of bird abundance was significantly greater between populations sharing the same cicada brood than between populations in the ranges of different broods. Species exhibited at least four partially overlapping temporal patterns. (I) Cuckoos (Coccyzus spp.) occurred in high numbers only during emergence years and subsequently declined in abundance. (2) Red-bellied Woodpeckers (Melanerpes carolinus), Blue Jays (Cyanocitta cristata), Common Grackles (Quiscalus quiscula), and Brown-headed Cowbirds (Molothrus ater) increased significantly 1-3 years following emergences and then declined. (3) Red-headed Woodpeckers (Melanerpes erythrocephalus), American Crows (Corvus brachyrynchos), Tufted Titmice (Baeolophus bicolor), Gray Catbirds (Dumetella carolinensis), and Brown Thrashers (Toxostoma rufum) were found in significantly low numbers during emergence years, underwent significant numerical increases in the following year, and then stabilized. (4) Wood Thrushes (Hylocichla mustelina), Northern Mockingbirds (Mimus polyglottos), Northern Cardinals (Cardinalis cardinalis), and House Sparrows (Passer domesticus) exhibited significantly deviant population numbers 1-2 years prior to emergences, below the long-term mean in the first two species and above the long-term mean in the latter two. These results suggest that the pulses of resources available at 13- or 17-year intervals when periodical cicadas emerge have significant demographic effects on key avian predators, mostly during or immediately after emergences, but in some cases apparently years foll

We used 37 years of North American Breeding Bird Surveys to test for effects of periodical cicada (Magicicada spp.) emergences on the abundance and spatial synchrony of 24 species of avian predators in hardwood forests of the eastern United States. Fifteen (63%) of the bird species exhibited numerical changes in abundance apparently associated with emergences of the local periodical cicada brood, and intraspecific spatial synchrony of bird abundance was significantly greater between populations sharing the same cicada brood than between populations in the ranges of different broods. Species exhibited at least four partially overlapping temporal patterns. (I) Cuckoos (Coccyzus spp.) occurred in high numbers only during emergence years and subsequently declined in abundance. (2) Red-bellied Woodpeckers (Melanerpes carolinus), Blue Jays (Cyanocitta cristata), Common Grackles (Quiscalus quiscula), and Brown-headed Cowbirds (Molothrus ater) increased significantly 1-3 years following emergences and then declined. (3) Red-headed Woodpeckers (Melanerpes erythrocephalus), American Crows (Corvus brachyrynchos), Tufted Titmice (Baeolophus bicolor), Gray Catbirds (Dumetella carolinensis), and Brown Thrashers (Toxostoma rufum) were found in significantly low numbers during emergence years, underwent significant numerical increases in the following year, and then stabilized. (4) Wood Thrushes (Hylocichla mustelina), Northern Mockingbirds (Mimus polyglottos), Northern Cardinals (Cardinalis cardinalis), and House Sparrows (Passer domesticus) exhibited significantly deviant population numbers 1-2 years prior to emergences, below the long-term mean in the first two species and above the long-term mean in the latter two. These results suggest that the pulses of resources available at 13- or 17-year intervals when periodical cicadas emerge have significant demographic effects on key avian predators, mostly during or immediately after emergences, but in some cases apparently years foll

In 1996, Government directives began a transition to conform logging in Western Australia's State forests to principles of ecologically sustainable forest management (ESFM). To place this in a historical context, we reviewed the history of the logging of jarrah Eucalyptus marginata forests to determine whether the volume of timber extracted and the main forest management practices employed was consistent with components of ESFM. While quantitative assessment proved difficult, usually the timber cut considerably exceeded the estimated annual increment of forested lands. Overcutting often distressed professionals, who strove to regulate logging despite social, political and economic pressures. Furthermore, despite recent major reductions in permissible timber cut, areas of productive State forest have declined after conversion to alternative vestings. Thus it is important to prevent overcutting continuing in the remaining production forests.Too few data exist on the health or condition of forest ecosystems before logging to document subtle impacts. However, overcutting has interacted with broad-scale threatening processes in their impacts on forest fauna. These changes are all associated with reluctance to invoke effective adaptive management in association with the precautionary principle. The historical survey suggests that ESFM cannot be achieved without a socio-political will to assert long-term sustainable practice in the face of short-term goals. This could be achieved in the current preparation of a new forest management plan for Western Australia.

We review recent studies of the impacts of disturbance on the fauna of the jarrah forest, southwestern Australia. In particular, we examine five case studies that provide alternative approaches to researching disturbance impacts. Assessing site-based studies of patterns of fire regimes lead us to argue that point measures of frequency are inadequate to understand scale and pattern across landscapes. Rather, extrapolating from site-based data to draw conclusions on landscape-scale changes may obscure fine-scale heterogeneity in disturbance, which is critical to the conservation of biodiversity. We review species-based studies and conclude that assessments of demographic trends are more effective than surveys in determining impacts, and providing early warning of declines because they highlight threatening processes. Furthermore, risk analysis, when critical aspects of the biology of participating species are weakly known, may lead to misclassification of species and poor decisions on conservation priorities. The review of recent impact studies of logging on jarrah forest fauna demonstrates that logging interacts with predation by foxes to threaten arboreal mammals. Hence, measures to protect threatened vertebrates benefit many species. However, while concentrating on proximate causes of fauna decline produces immediate conservation gains, long-term conservation requires an understanding of both proximate and ultimate causes and their interaction. We urge the acquisition of reliable, site-based demographic data that allows predictive modelling for species, and hence testing of alternative hypotheses regarding impact, distribution and decline. We also seek the integration of data and approaches to enable landscape-scale patterns to be discerned and interpreted for effective conservation planning.

Community Conservation Assessment For Rich Woods Community

This technical note is a product of the Ecosystem Management and Restoration Research Program (EMRRP) work unit titled "Improved Methods for Ecosystem-Based Habitat Management at Corps Projects." The objective of the work unit is to provide appropriate technology on managing wildlife species and their habitats using ecosystem-based strategies. The emphasis is on methods that improve natural resources for a variety of animals rather than single species. Bottomland hardwoods represent an important natural resource associated with stream and river floodplains throughout the Southeastern United States. These forest systems support a complex array of plant and animal species that are uniquely adapted to flood conditions and alternating dry periods. Moreover, these habitats often support a higher diversity of avifauna than adjoining upland habitat and may act as sources for bird populations, which permits the maintenance of regional diversity in highly fragmented landscapes. Corps projects are often associated with lakeshores, rivers, and streams; thus, there are many opportunities to identify and - manage large areas of bottomland systems on Corps lands in the Southeast.

Characterization of fuel consumption and heat pulse into the mineral soil on the Jacob Branch and Devil Den units in North Carolina

Impacts of Ground Extraction Systems During Harvest of Hardwoods on Steep Slopes

A model for Ultrahigh Frequency radiowave propagation through a forest of tree trunks, branches, and leaves which had been first described in a previous report has been extended. Forest characterization includes the dielectric properties of green wood and leaves, tree trunk diameter distributions, branch orientation, and canopy structure. Plots of the effective dyadic susceptibility and specific attenuation for homogeneous and non- homogeneous forests of tree trunks are presented. The theory of the anisotropic forest slab model is extended to include the forest floor and multiply-reflected space and lateral waves. Basic transmission losses versus frequency for various radiolink geometries are plotted, as are the responses to five-nanosecond pulses at 600 MHz. Incoherent multiple scattering in a two-dimensional forest of tree trunks, small or large with respect to the wavelength, is studied. Plots are shown for single-tree scatter patterns, albedos, and total cross-sections versus frequency, as well as normalized coherent and incoherent scattering intensities versus distance, and normalized frequency-and space-correlation functions. (Author), See also Rept. no. CTR-108-01, AD-A130 399.

A model for UHF radiowave propagation through a forest of tree trunks, branches, and leaves is developed using the discrete scattering theory of Foldy and Lax. The forest is represented as a time-invariant ensemble of tree trunks, branches, and leaves all having prescribed location and orientation statistics. Tree trunks are modelled as infinitely-long, circular, lossy- dielectric cylinders; branches as finitely-long, circular, lossy-dielectric cylinders; and leaves as flat, circular, lossy-dielectric discs. Mathematical expressions are found for the effective dyadic susceptibilities of the equivalent continuous medium and for the specific attenuation associated with the (coherent) fields. Using biophysical parameters typical of a deciduous, hardwood forest, these expressions are found to be in reasonable agreement with experimental results. An anisotropic half-space model of the forest is reflected-, and lateral wave components of the mean field presented for a pulse of a few nanoseconds duration and a frequency of 600 Magahertz. A preliminary analysis shows the importance of the random (incoherent) field at a distance of one kilometer and at frequencies above 100 Megahertz. (Author)

Manuka Downs is a coastal property in North Canterbury, between the Hurunui and Blythe Rivers. The farm occupies a land surface of uplifted sediments mantled with loess and subsequently dissected by several small streams that have cut deep channels through the sediments close to the coast. Altitudes range from about 30-150 m above sea level. Manuka Downs covers about 1 000 acres and of this area about one third supports more or less dense kanuka low forest with associated hardwood species in gullies and manuka along disturbed margins. This large area of kanuka (often called white manuka) has undoubtedly given rise to the name of the farm. It is certainly the largest area of continuous kanuka in the Motunau Ecological District, and probably in the whole of North Canterbury.

Hardwood Regeneration Conference Proceedings 1982